322 PROFESSOR LETTS ON PHOSPHORUS-BETAINES. 
crystallising in warty masses, the other in plates and needles. On dissolving 
either of these in boiling water an insoluble residue is left, which appears to be 
bromide of lead. (It melts to a yellow liquid, and does not char when heated). 
The filtered solution deposits needles or plates on cooling, and very little of the 
warty crystals ; and on again recrystallising, the salt is obtained almost free 
from the latter. 
The composition of the lead salt varies, and although a large number of 
specimens were examined no two of them yielded the same numbers. The 
crystalline form was often entirely different, and was altered by recrystallisation 
of the salt. Moreover, a distinct smell of triethyl-phosphine was always noticed 
when carbonate of lead was employed in its preparation. 
The author could arrive at no definite conclusion as to the composition of 
these sparingly soluble lead compounds. He thinks it advisable, however, to 
give the numbers obtained— 
I. LE WY, IV. V. VI. 
Lead, . ; : 49:4 49:7 44°6 44:5 43°7 68:2 
Bromine, : , 37:2 36'6 40:0 40:0 a 26°7 
VIL. VIII. IX. Ke XI. 
end : ; Of ee bcd 52°4 39°6 
Bromine, f ‘ 25:2) 452 42:0 42°5 43:0 
J. and IT. obtained with acetate of lead, and produced from a hot solution. 
TLL; EV.,.end Vv, os % - BICOL | a 
VI. and VII. obtained as I. and II. 
VIIL, IX., X., and XI, obtained with carbonate of lead. 
CH,—CO 
B= CTO. = CHL). PC 
Spal 2 ( 24*5/3 ‘sal 
Lead. Bromine. 
Calculated for 8 + PbBr, ; : 38'1 29°4 
4 B+ 2PbBr,  . : 45°5 ODD 
i B+5PbBr,  . ; 48°7 37°6 
x B+4PbBr, . : 50-4 38'9 
The preceding results having failed to establish the composition of the pro- 
duct, other reactions were sought for which would decide this point. In con- 
sidering how to attack this problem the question presented itself, is it not 
possible that the action of triethyl-phosphine on bromacetic acid gives rise to 
an isomer of hydrobromate of triethyl-phosphorus-betaine? Such a pheno- 
menon would not be extraordinary, as chloracetic, bromacetic, and iodacetic 
acid do not always act in the same manner. 
